The Vatican has spent over three million euros restoring the last frescoes ever painted by Michelangelo which may have unveiled a new self-portrait ( blue turban). Photo: ANSA

Restorers claim that a bearded man wearing a blue turban in the Crucifixion of St Peter bears a striking resemblance to portraits and bronze busts of the artist.

"It's an extraordinary and moving discovery," said the Vatican's chief restorer, Maurizio De Luca. "The self-portrait is one of three knights on the left-hand top corner of the fresco who wears a lapis lazuli blue turban. His features are very similar to other known portraits of Michelangelo."

The fresco shows the moment at which St Peter was raised on the cross by Roman soldiers, his face showing suffering but also defiance.

It is not the first time the renowned Italian master included his portrait in one of his works.

He painted a cleverly disguised self-portrait into The Last Judgment in the Sistine Chapel.

His face appears in a ghoulish image of St Bartholomew, with the saint holding a knife and his skin after it has been flayed from his body.

The Vatican spent more than three million euros (£2.6 million) restoring the Crucifixion of St Peter along with another important fresco, the Conversion of Saul.

Completed between 1542 and 1550, they were the last frescoes Michelangelo ever painted.

"After the Pauline Chapel he ended his life as a painter and dedicated himself only to sculpture and architecture," said Mr De Luca.

The frescoes adorn either side of the Pauline Chapel, which is closed to the public and used only by the Pope and his closest entourage.

The chapel, in the Vatican's Apostolic Palace, was commissioned by Pope Paul III in 1537 and completed in 1540.

Michelangelo began work on the Pauline Chapel murals in 1542 after he had finished the work in the Sistine Chapel, finishing the project at the age of 75.

Pope Benedict XVI will officially inaugurate the restored chapel with an evening prayer service on Saturday.

The project was funded with the help of donations from around the world, including from Britain, the US and Ireland.